• 대한토목학회논문집
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• 제28권5A호
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• pp.757-764
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• 2008

본 연구는 농도조건을 달리한 시험용액에 침지한 모르타르의 내구성을 평가하기 위하여 수행되었다. 3종류 시멘트 모르타르를 제조한 후, ${SO_4}^{2-}$ 이온의 농도가 4225, 8450, 16900 및 33800 ppm인 4종류 황산나트륨 용액에 540일간 침지하였으며, 침지재령별 압축강도 및 선형팽창을 측정하므로써 모르타르의 황산염침식 저항성을 실험적으로 평가하였다. 실험결과에 의하면, 고농도 황산나트륨 용액에 침지한 모르타르 공시체가 가장 심한 성능저하 현상을 나타내었다. 특히, 고농도 환경에서 모르타르의 팽창 특성은 사용된 시멘트의 $C_3A$량과 직접적인 관련이 있었으며, GGBS를 대체한 SGC 모르타르는 조직구조의 투수성이 상대적으로 낮은 탓으로 인하여 시험용액의 농도조건에 관계없이 우수한 황산염침식 저항성을 나타내었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.133-136
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• 1994

This study is to investigate properties of the ultra high-strength concrete using silica rume and fly ash. For this purpose, the properties of fresh concrete and hardened concrete are examined with varing water-cement ratio, silica fume and fly ash content and so on. From these test results, it is possible to maunfacture the miximum strength of 1, 200kg/$\textrm{cm}^2$ with cement content 800kg/$\textrm{m}^3$, 18% water-cement ratio, 105 silica fume content.

• 한국산림과학회지
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• 제87권1호
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• pp.62-73
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• 1998

이 연구(硏究)는 계류수(溪流水)에서 수질평가항목(水質評價項目)의 설정시(設定時) 중요한 인자(因子)인 양(陽)이온($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$)과 음(陰)이온($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$)에 미치는 영향요인을 구명(究明)함으로써 계류수질평가기준(溪流水質評價基準)을 정립(定立)하기 위한 기초자료(基礎資料)를 제공(提供)하기 위하여 서울대학교(大學校) 농업생명과학대학(農業生命科學大學) 부속(附屬) 관악수목원내(冠岳樹木園內) 산림소유역(山林小流域)의 3개 조사구(調査區)에서 수행(遂行)하였다. 1996년 7월 1일부터 1997년 8월 31일까지 강수(降水), 수관통과우(樹冠通過雨), 토양수(土壤水) 그리고 계류수(溪流水)의 수질동태(水質動態)를 분석(分析)한 결과(結果), 계류수(溪流水)에 용존(溶存)되어 있는 $Cl^-$이온은 강수(降水)나 수관통과우(樹冠通過雨)보다는 토양수(土壤水)에 용존(溶存)되어 있는 $Cl^-$이온과 유의(有意)한 상관관계(相關關係)를 나타내었으며, 토양수(土壤水)에 용존되어 있는 $NO{_3}^-$이온은 강수(降水)에 용존되어 있는 $NO{_3}^-$이온과 유의(有意)한 상관관계(相關關係)를 나타내었다. 또한 토양(土壤) A층(層)과 B층(層)의 토양수(土壤水)에 용존되어 있는 양(陽)이온($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$)과 음(陰)이온($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$)은 통계적(統計的)으로 유의(有意)한 상관관계(相關關係)를 나타내었다. 강수(降水)에 용존(溶存)되어 있는 $NO{_3}^-$이온과 $SO{_4}^{2-}$이온의 평균농도비(平均濃度比)는 약 0.66으로 강수(降水)에는 $NO{_3}^-$이온보다는 $SO{_4}^{2-}$이온이 더 많이 함유(含有)되어 있었다. 전체 조사구에서 강수(降水), 수관통과우(樹冠通過雨), 토양수(土壤水)의 음(陰)이용량(量)은 계류수(溪流水)에 용존(溶存)하는 음(陰)이온량(量)과 유의(有意)한 상관관계(相關關係)를 나타내었으며, 강수(降水), 수관통과우(樹冠通過雨), 토양수(土壤水), 계류수(溪流水)에 용존(溶存)되어 있는 이온총량(總量)의 평균값의 크기는 토양수(土壤水)(B층(層)>A층(層))>수관통과우(樹冠通過雨)(리기다소나무림 > 벚나무림 > 서어나무림) > 계류수(溪流水) > 강수(降水)의 관계(關係)이었다.

• 한국세라믹학회지
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• 제22권1호
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• pp.25-34
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• 1985

The states of alkali occuring in Portland cement clinker were studied. Potassium was added to raw mixture by there kinds ; $K_2SO_4$, $K_2CO_3$ and KOH. In case of $K_2CO_3$ and KOH addition the new state of unstable alkali was found when alkakli content is high and $SO_3$ content is low in the clinker. Unstable state of highly basic free 4K_2O$ causes lowering burnability much more than alkali sulfate especially at the early stage of burning. Lowered burnability by 4K_2O$ became more serious with higher LSF. Unstable free-4K_2O$ which is readily soluble with water reacts with gypsum to form $Ca(OH)_2$ and syngenite as soon as water is added. As a results the liberation rate of heat of hydration at the early hydration process(1st peak) was increased.

• 한국해양공학회지
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• 제14권3호
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• pp.66-71
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• 2000

The main objectives of this study are to carried out in order to evaluate strength development of Fly Ash concrete containing various amounts of Fly Ash such as 0%, 10%, 20% and 30%. The experimental variables included in this test program consist of content of Fly Ash, concrete strength and chemical activation. As Fly Ash increases, air content, strength development of concrete and slump loss of normal strength concrete were gradually decreased. The inclusion of Na$_2$SO$_4$increased the short-term strength of concrete that contains Fly Ash. In addition, the strength development of concrete that contains Fly Ash and Na$_2$SO$_4$were improved.

• 한국식품영양학회지
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• 제32권6호
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• pp.598-610
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• 2019

The purpose of this study was to investigate the quality characteristics and antioxidant activity by collecting four times on six samples of Jeonbuk regional soybean pastes (Doenjang) traditionally prepared for this study. The water content of samples decreased according to progress of the aging period and the water content of the fourth sample collected was 42.40~59.64% (p<0.05). The salinity of the fourth Doenjang samples was 11.80~18.60%. The amino-type nitrogen content was 122.67~540.33 mg% immediately after the preparation of Doenjang in the Jeonbuk region and the content of the fourth collection samples increased from 251.49 to 982.36 mg% (p<0.05). The isoflavone glycosides decreased but daidzein, genistein and glycitein, which are aglycones, increased during aging periods. The total polyphenol content of the fourth collected samples was 11.99~19.27 mg GAE/g (p<0.05). The DPPH radical scavenging activity, ABTS radical scavenging activity and FARP of the fourth Doenjang samples were 51.88~81.21%, 84.14~90.32%, and 1.08~3.11 mg Trolox/g, respectively. As a result of quality analysis on Doenjang, the superiority of traditional Doenjang has been proven by the increase of amino nitrogen content and antioxidant activity according to the aging period. However, factor analysis on quality differences of regional Doenjang should be conducted to ensure standardization and quality improvement.

• 한국식품영양학회지
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• 제37권4호
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• pp.180-188
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• 2024

In this study, chemical properties and functional ingredients of ginger and ginger pomace discarded after juice were analyzed. Ginger and ginger pomace were subjected to hot air drying, steaming, followed by hot air drying, soaking in vitamin C for 1 hour and 3 hours. When soaked in vitamin C for 3 hours, the moisture content was highest at 9.2% for ginger and 7.3% for ginger pomace. Among inorganic ingredients, the potassium (K) content was high at 2,633.6 mg% in hot air-dried ginger after steaming and at 1,584.3 mg% in ginger pomace. Total flavonoid content of ginger pomace was high at 67.3 mg/g when soaked in vitamin C for 3 hours. Gingerol content was the highest at 9.8 mg/g when ginger was dried with hot air. It was 10.5 mg/g in ginger pomace. After ginger pomace was steamed and dried with hot air, shogaol content was as high as 2.0 mg/g.

• 한국식생활문화학회지
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• 제16권5호
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• pp.478-482
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• 2001

This study was conducted to investigate the difference of general feature and ginsenoside content of 6 years old ginseng root among different grade of roots. Total weight of a 1st grade-6 years old ginseng root was 115.1g and weight, length, diameter and specific gravity of main root were 64.68g, 8.39cm, 3.31cm and 0.96, respectively. Main root of 1st grade ginseng root was larger in size and specific gravity and more heavy than that of End or 3rd grade of the roots. Though crude saponin contents were not so different among the different grade of roots, but ginsenoside Rb1, Rg1 and Re content were higher in 1st grade of root than that of 2nd or 3rd grade of root. Those ginsenosides were located mainly in periderm and cortex.

• Journal of Plant Biology
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• 제5권2호
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• pp.6-12
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• 1962

For the comparison with the previous paper (4) the present report deals with the absorption and metabolism of urea and other nitrogen ions in barley seedling absorbed through root. 1. The amount of nitrate in barley treated with urea reach it peak on the 8th day. NO3 on the 4th, NH4 on the 6th or 8th, respectively. 2. The ammonia content in urea group reaches its peak on the 6th day but other groups on the 4th day. The present data in the urea group show to shorten 4 days compared with that of the previous paper(4). 3. the content of total amide from the present data aare gradully increased on all of the groups during this experiment. These are agreement with the result of the previous paper (4). 4. the alcohol solution nitrogen in the urea gorup shows the similar tendency to the NaNO3 group but reaches it peak 2 days later than in the (NH4)2SO4 group. 5. The content of total nitrogen in the urea series has the lowest amount at the beginning while the richest from the 4th day after. These would be explained on that the absorption of urea is delayed and the PH in the urea solution does not change, so called "physiological neutrality". The author should like express his sincere thanks to Prof. M.J.Lee of Seoul National University for his valuable advices.e advices.

• 아시안잔디학회지
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• 제4권2호
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• pp.119-123
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• 1990

The experiment was carried out to analysis the differences between classification by the estimate of survey character and thatch accumulation. The results obtained are summarized as follows:1.BentgrassPenncross: had the highest thatch accumulation. 2.Thatch accumulation of creeping season turf was higher than that of bunch type and thatch accumulation of cool season turf was higher than that of warm season turf. 3.The coverage rate was 43.3%, so turf quality was not good. 4.Bermudagrass(Guymon) had the highest content of lignin in thatch and coverage rate. 5.Species had significant negative correlation with the content of lignin.